tinkerboard: update README with improved setup instructions

Signed-off-by: deadprogram <ron@hybridgroup.com>

platforms/tinkerboard/README.md

@@ -14,6 +14,88 @@ You would normally install Go and Gobot on your workstation. Once installed, cro
 go get -d -u gobot.io/x/gobot/...
 ```
 
+### Enabling GPIO pins
+
+To enable use of the Tinker Board GPIO pins, you need to perform the following steps as a one-time configuration. Once your Tinker Board has been configured, you do not need to do so again.
+
+- Create a group "gpio"
+
+Create a Linux group named "gpio" by running the following command:
+
+```
+sudo groupadd -f --system gpio
+```
+
+If you already have a "gpio" group, you can skip to the next step.
+
+- Add the "linaro" user to the new "gpio" group
+
+Add the user "linaro" to be a member of the Linux group named "gpio" by running the following command:
+
+```
+sudo usermod -a -G gpio linaro
+```
+
+If you already have added the "gpio" group, you can skip to the next step.
+
+- Add a "udev" rules file
+
+Create a new "udev" rules file for the GPIO on the Tinker Board by running the following command:
+
+```
+sudo vi /etc/udev/rules.d/91-gpio.rules
+```
+
+And add the following contents to the file:
+
+```
+SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'"
+SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'"
+```
+
+Press the "Esc" key, then press the ":" key and then the "q" key, and then press the "Enter" key. This should save your file. After rebooting your Tinker Board, you should be able to run your Gobot code that uses GPIO.
+
+### Enabling I2C
+
+To enable use of the Tinker Board I2C, you need to perform the following steps as a one-time configuration. Once your Tinker Board has been configured, you do not need to do so again.
+
+- Create a group "i2c"
+
+Create a Linux group named "i2c" by running the following command:
+
+```
+sudo groupadd -f --system i2c
+```
+
+If you already have a "i2c" group, you can skip to the next step.
+
+- Add the "linaro" user to the new "i2c" group
+
+Add the user "linaro" to be a member of the Linux group named "i2c" by running the following command:
+
+```
+sudo usermod -a -G gpio linaro
+```
+
+If you already have added the "i2c" group, you can skip to the next step.
+
+- Add a "udev" rules file
+
+Create a new "udev" rules file for the I2C on the Tinker Board by running the following command:
+
+```
+sudo vi /etc/udev/rules.d/92-i2c.rules
+```
+
+And add the following contents to the file:
+
+```
+KERNEL=="i2c-0"     , GROUP="i2c", MODE="0660"
+KERNEL=="i2c-[1-9]*", GROUP="i2c", MODE="0666"
+```
+
+Press the "Esc" key, then press the ":" key and then the "q" key, and then press the "Enter" key. This should save your file. After rebooting your Tinker Board, you should be able to run your Gobot code that uses I2C.
+
 ## How to Use
 
 The pin numbering used by your Gobot program should match the way your board is labeled right on the board itself.
@@ -34,6 +116,9 @@ $ GOARM=7 GOARCH=arm GOOS=linux go build examples/tinkerboard_blink.go
 
 Once you have compiled your code, you can you can upload your program and execute it on the Tinkerboard from your workstation using the `scp` and `ssh` commands like this:
 
+Once you have compiled your code, you can you can upload your program and execute it on the Raspberry Pi from your workstation using the `scp` and `ssh` commands like this:
+
 ```bash
-echo "todo"
+$ scp tinkerboard_blink linaro@192.168.1.xxx:/home/linaro/
+$ ssh -t linaro@192.168.1.xxx "./tinkerboard_blink"
 ```